Method of producing multivalent metal



- "Robert'E. Hulse, Darien,Cphng assignorto volatilized.

12,916,374 METHOD OFPRODUCINGMULTIVALENTI National. 7 Distillers and Chemical Corporation, New York, N.Y., :acorporationof Virginia Y 7 f No' Drawing. Application March 13, 19157.

7 Claims.- (Cl. 75-8445) invention relates to anew, and useful process for the manufacture of metal 's'pong'e. 'More particularly,

sponge from zirconium tetrahalide metalsis wellpknowninthe-prior art. :I nan effort t avoid certainj'op the inventiongpertainsto the production of zirconium erational difiicultM of the prior art i processes,- it has beenrecentlyiproposed that metals such 1 United States Patent-O :and to permit the .reduced ice ofaabout ;800 to 1000? C. under atmosphericpressure for about .10 to 20.hours to. melt the .alkali metal halide metal toagglomerate. After sintering, the alkali metal halide can either be distilled 'ofhunder-a vacuum ofaboutOLl to 10 microns or leached using conventional techniques such as washing .with mineral acid and/ or water. It will be understood, that the reaction may be carried out by gradually heating the reactionmixture through the temperature ranges set forth above.

It will be further understood, that metallic impurities as zirconium may readilybe prepared by firstpartially reducing the metal halides with-"'anfalkali metal under carefully controlled conditions to obtain a'freeflowing,

{finely divided. solid, dry mixture of metal 'subha'lide-alkali metal halide. complexes. The resulting reaction mixture is then further reacted withadditional alkali metal to complete the reduction to the metal 'in a combi'ned re- "duction "and sintering operation. The metal produced by following the .aforedescrib'ed process while meeting most specifications. often hasanfundulyhigh halogen ion :content.

In accordance with'the present invention, it has now been found that an'eXceIlent-metaJproduct having a halogen ion content ofless than about 0.2% can be obtained, directly from the metal f'subhalide-alkali metal halide complex mixture. More specifically, it has been found that the" metal subhalide-alkali metal halide complex mixture, prepared as described below, may -be heated directly under prescribed conditions to produce the desired zirconium'metal sponge. Theprocess of the invention is carried out-by heating the complex mixture at a temperatureofabout 500 to 1700 'C., and a pressure of about 0.01Fto 100 Hgypreferably about 0.1 to 10.0 mm. 'Hg. Though --the exact nature of the 'tetrahalide volatilized, the remaining reaction products,

ite. the reduced metal and the alkali metal halides, may be further treated in a number o f ways to recover the desired metal sponge. One method of operation comprises continuing the heating'under vacuum until .a tem- :perature of about 700 to rll000 C. .is reached. At this -temperature the alkali :metalhalide will volatilize and is recovered overhead. In general, this treatment at elevated temperatures will take about l to hours, though it will be understood that heating need only ;be carried 'outuntil substantially all of the. alkali .metal halide is Another method of separating athe alkali .metal halide from the reduced'rnetal comprises heating ;the disproportionated reaction mixture, following the .volatilization of the metal tetrahalide, .at ,a temperature present in the crude feed mixtures in the formof their Ihalides also will be separated from the reducedmetalsin the course of carrying out the process as described above.

As noted above, the feed utilized in theprocess of the invention comprises .thereaction product mixture :ob-

tained by partially reducing a metal tetrahalide with an alkali metal. For the purpose of a more complete description, a process using zirconium tetrachloride as the metal halide and metallic'sodium as the alkali metal reduring agent'will be set forth. Zirconium tetrachloride is pas'sedwith tmetallic'sodium into an agitated bed of sodium chloride, which may contain some reduced zirconium chloride or metal from a previous operation, under'an-inert gas,'e.g. argon, atmosphere. The amount of sodium employed will be less than the-stoichiometr'ic amount required to completely reduce the zirconium tetrachloride to zirconium metal. Preferably, the amount of sodium employed will constitute about 25 to "50% of the stoichiometric amount. The reaction is carried out at a temperature above the melting point of sodium but below the melting-point of the sodium chloride, more specifically at about to 400 C., and preferably about 150 to 200 C. The bed, containing the reaction mixture as well as ;the reaction products, .is maintained in .astate of agitation by vigorous mechanical stirring or inert gas fluidization. After the reaction has been completed, a free flowing, .finely divided solid dry reaction product mixture is recovered from the .reaction vessel.

In accordance with the process described above, feed useful forthe present metal manufacture method is prepared, for' example, by reacting 49.5 parts of zirconium tetrachloride vapor with 9.75 parts of sodium, this amount screw conveyor. The exact nature of the 'reaction'product mixture is difiicult to determine,zthough it has been established that free zirconuim and sodium chloride are not present. However, the reaction products do conform to the empirical formula M ZrX wherein 'M corresponds to the alkali metal employed as the reducing agent and X is the particular halogen used. In accordance with the preferred method of carrying out the inventionthe atomic ratio of azb is about 1:4 to 2:4. Since these reaction products have not been definitely proven to be chemical compounds as contrasted with mixtures, they will be referred to throughout this specification as chemical complexes or compositions.

Though only metallic sodium has been described above as the reducing agent, it will be understood other alkali metals such as lithium, potassium, rubidium and cesium may also be employed. In addition to chlorine as the preferred halogen,bromine and iodine may be effectively utilized. It should also be noted that in place of .zirco EXAMPLE I A charge of 8.9 grams of Na ZrCl (obtainedas the.

50% reduction product by reacting ZrCl with "metallic sodium) was'placed in a tantalum boat and heated to the successively higher temperature tabulated below untilonly zirconium metal remained as the residue. The byproduct ZrCl; and NaCl were collected separately in the furnace. The more volatile ZrCl4 was collected at a greater distance from thefurnace. The NaCl was distilled off at pressures in the range of about 0.1 to 10 microns The results were as follows;

cooler parts of the glass tube protruding from the muflie Table I Actual Theoret- Fraction Temp., Weight, ical 1 0. g. Weight,

B 1 7004340 3.890 3. 73 O 3 (Residue) 1.757 1. 46

Thou s. 945 8.92 A

l Substantially ZrOh.

I Substantially NaCl:-a Na analysis retical Na in N aCl (Le. some ZrGli was present in Fraction B). Sponge Zr metal.

The discrepancy between the actual and calculated analysis probably arises from the fact that the feed material may vary somewhat from the 50% reduction point. The feed powder may, for example, .vary between about 45 and 55% reduction.

- EXAMPLE II A charge of about 8.69- grams of 50% reduced zrcl corresponding to the empirical formula Na zrClg was vola'tilized later at the higher temperatures by heating for 34.6% as against 39.4% for thentwo hours. The results are set forth below;

Table II Erection Tgnn, Weight, Remarks A 500-700 3. 29 ZrCl contg. 0.25% No.01. B 800-960 3. 45 NaCl (36.5% N O (Residue) 1. 9 5 Sponge Zr Metal (0.114% Cl).

Total s 69 EXAMPLE III A charge of about 10 reduced ZrCL; reaction product mixture was heated under vacuum as set forth in-Examples I and II with the excepgrams of the approximately 50% sodium.

chlorine.

multivalent metal is. recovered metal halide by leaching.

. .tion that NaCl volatilization at 0.1 to10 microns Hg pressure was carried out at a temperature of 900 to 1000" C. for 5 hours. Results are as follows:

It should be noted from the above II failed to give a z irconiumproduct having a lower chlorideion content. This. possiblyresults from the fact that even with a very open structure the zirconiumrnetal It will be apparentthat the. zirconium etrachlioiridel and sodium. hl d brmsdi o thf v fi nlm rea be employedto advantage in the 'reductionstage andthat this constitutes an additionaliand. significant advantage over prior art processes. Q. i

It will be further understood that jthe reactants and operating conditions set forth in thejfor'egoingf specific embodiments may be. varied withinjthe limits; indicated in the. more general description of the invention.

Vlfhatisclaimedis:. q H

w 1. A process for preparing a multivalent metal selected from the group Lc nsistirigTofZircOniHm, titanium; niobium, and molybdenumgwhich consists otta) reacting a higher valent halide of said metal with about 25 .to. 50% of the .stoichipmetric amount of an a lkalimetal required to completely reduce the higher. jvalent {metal halide to metal in. an agitated bed. of alkali metali hali de to obtain a finely. divided reaction. productcorresponding to the empirical formula'M RX wherein M is the. alkali metal, R is the ,multivalent rnetalg'X is :a halogen selectedfrom the group consisting rof;chloriney brornine and iodine, and the 'ratio of a to b is withinthe range fof about 1:4.to 2:4, (b) heatingsaid finely divided reaction product at a temperature of about 500 to. 7001-(110,disproportionate said product andgto obtain a re action product rnixture comprising said multivalent metal, a 'higher. valent halide of said metaland alkali metal halide, (a) heating said reaction'product mixture at a temperature of about 800 to 1000 ,C. toagglomerategsaid multiva lent metal prodnet, and (d) recovering said agglomerated .multivalent metal. w i

2. Theqproc ess of. claim ,ll wherein said multivalent metal is zirconium I l 3. The process of claim =1 wherein said alkali metal is .4. The ofyclaim l;wherein said halogen is 5.The process ofrclaim 1: ,whereinthe agglomerated from -by-product alkali 6. A process forupreparing zirconium metal which consists of. (a)vreactin'g zirconium tetrahalide with about 25 to 50%"of:the. stoichiometricamoun't of an alkali metal required to completely reduce the zirconium tetrahalide to zirconium .metal in an agitated bed .ofalkali metal halide to obtain a finely divided reaction product corresponding'to the empirical formula M ZrX wherein 3 M is thealk ali me'tal, X isa halogen selected' from the group consisting of chlorine, bromine and iodine, and the ratio of a to b 'islwith'inf the range of about 1:4 to 2:4, b) heating said finely divided reaction product at a temperature ofabout 500 to 700 C. to disproportionate datajthat the increased distillation time over thatemployed in Example said product and to obtain a reaction product mixture comprising zirconium metal, zirconium tetrahalide and alkali metal halide, and volatilizing said zirconium tetrahalide, (c) heating the remaining reaction product mixture at a temperature of about 800 to 1000 C. under vacuum to agglomeratc said zirconium metal and to volatilize said alkali metal halide, and (d) recovering said agglomerated zirconium metal.

7. The process of claim 6 wherein said alkali metal is sodium.

References Cited in the file of this patent UNITED STATES PATENTS McKinley Apr. 26, 1955 Hansley Feb. 25, 1958 Wade Apr. 15, 1958 Kingsbury May 20, 1958 FOREIGN PATENTS Great Britain -1 Nov. 3, 1954 Great Britain Dec. 22, 1954 

1. A PROCESS FOR PREPARING A MULTIVALENT METAL SELECTED FROM THE GROUP CONSISTING OF ZIRCONIUM, TITANIUM, NIOBIUM, AND MOLYBDENUM, WHICH CONSISTS OF (A) REACTING A HIGHER VALENT HALIDE OF SAID METAL WITH ABOUT 2K TO 50% OF THE STOICHIOMETRIC AMOUNT OF AN ALKALI METAL REQUIRED TO COMPLETELY REDUCE THE HIGHER VALENT METAL HALIDE TO METAL IN AN AGITATED BED OF ALKALI METAL HALIDE TO OBTAIN A FINELY DIVIDED REACTION PRODUCT CORRESPONDING TO THE EMPIRICAL FORMULA MARXB WHEREIN M IS THE ALKALI METAL, R IS THE MULTIVALENT METAL, X IS A HALOGEN SELECTED FROM THE GROUP CONSISTING OF CHLORINE, BROMINE AND IODINE, AND THE RATIO OF A TO B IS WITHIN THE RNGE OF ABOUT 1:4 TO 2:4, (B) HEATING SAID FINELY DIVIDED REACTION PRODUCT AT A TEMPERATURE OF ABOUT 500* TO 700*C. TO DISPROPORTIONATE SAID PRODUCT AND TO OBTAIN A REACTION PRODUCT MIXTURE COMPRISING SAID MULTIVALENT METAL, A HIGHER VALENT HALIDE OF SAID METAL AND ALKALI METAL HALIDE, (C) HEATING SAID REACTION PRODUCT MIXTURE AT A TEMPERATURE OF ABOUT 800* TO 1000*C. TO AGGLOMERATE SAID MULTIVALENT METAL PRODDUCT, AND (B) RECOVERING SAID AGGLOMERATED MULTIVALENT METAL. 